The increasing use of silver nanoparticles (AgNPs) in various products leads to their presence in the aquatic environment. The dissolution of AgNPs is an important property that has a direct impact on human health and the natural environment. Understanding the dissolution behaviour of nanoparticles in liquid suspensions is essential for predicting their potential toxic effect in organisms, ranging from viruses and bacteria to humans. Moreover, the dissolution rate of nanoparticles can explain some of their disinfecting properties, which are important for sanitation. The objective of this study is to determine the dissolution behaviour of AgNPs in pure water and to improve our understanding of its most fundamental principles. Dissolution constants of AgNPs found in literature span over a wide range, indicating that improvement of the measuring method is needed. AgNPs in this study were produced in a principally impurity-free way, from the gas phase, after which they were transferred into liquid solutions. The purity of the particles produced in this study is in principle higher compared to those used until now, which allows for higher precision in determining the dissolution constant. Measuring the silver ion concentration in the resulting liquid solutions (i.e., after introducing the AgNPs in the solution) with an ICP-MS at specific time intervals gave direct information on the dissolution kinetics. The experiments were repeated with particles having diameters from 7 to 12 nm and, as expected, dissolution kinetics were found to be highly dependent on particle size. The determined dissolution constants are in the same order of magnitude as the values reported in literature. To further improve the reliability of the measurements, the experiment needs to be repeated using different methods for transferring the particles into the liquid, given that the used bubbling method showed deficiencies.